Magnetic Field Suppression of the Martensitic Transformation in Mn‐Based MnNi(Fe)Sn Metamagnetic Shape Memory Heusler Alloys

Heusler metamagnetic shape memory alloys (MMSMAs) show a large functional response associated with a first order martensitic transformation (MT). The strong magneto-structural coupling together with mixed magnetic interactions enable controlling this MT by means of magnetic field resulting in different multifunctional properties such as giant magnetoresistance, metamagnetic shape-memory effect (MMSM), or inverse magnetocaloric effect (MCE). Both the shift rate of MT as a function of the magnetic field and its eventual suppression are key parameters for the development of all these effects. In this work we present our findings regarding the use of strong steady magnetic fields, up to 33 T, to study in detail the magnetic field induced MT and its suppression in MnNi(Fe)Sn MMSMAs, leading to creation of the T-0H phase diagrams of the MT. Moreover, we have analyzed the impact of Fe - doping and, as direct consequence, the magnetic coupling on the suppression of the magnetostructural transformation.